1. Field of the Invention
The present invention relates to radio front-end transceiver architecture and packaging. In particular, the present invention relates to a gallium arsenide (GaAs) MMIC-based front-end transceiver integrated chip set for E-Band applications.
2. Background of the Invention
The present application is directed to “millimeter wave” frequencies which generally comprise frequencies above 40 GHz. In particular, there has been a tremendous interest in utilizing the E-Band portion of the electromagnetic spectrum because of the inherently wide bandwidth available in the E-band frequency range.
E-Band (also sometimes referred to as W-Band) is defined by the FCC as frequency ranges 71–76 GHz, 81–86 GHz and 92–95 GHz. The FCC has set aside E-band primarily for commercial use. By operating at millimeter wave frequencies, digital radios gain access to large blocks of bandwidth that can support emerging high-data rates and multiple-access markets. Some, industry proponents foresee using millimeter frequencies as a means of overcoming the “last mile” bottleneck that hampers broadband usage.
Practical applications of millimeter wave technologies can be generally categorized into two basic categories: (1) communications (point-to-point, point-to-multipoint, local multipoint distribution systems, indoor communications, wireless local area networks), and (2) automotive radar, industrial sensors, and imaging. There are also some DoD military applications which utilize E-band.
In today's world of miniaturization, there is an ever-increasing industry pressure to reduce the size and cost of E-band communication chip sets. This pressure has driven designers to develop E-band transceivers with higher levels of integration. Achieving the goal of maximum integration is not as trivial as replacing external components with on-chip components. Instead, it typically requires a reconfiguration of the front-end design. And since E-Band transceiver front-ends are considered key elements in the expanding millimeter wave based communications technologies, efforts are being directed toward making E-band transceivers smaller, lighter, more power efficient, and less expensive. This has resulted in new E-Band front-end architectures with fewer off-chip components.
A disadvantage of the current known prior art methods of designing and integrating more compact E-Band chip sets is that most suppliers of MMIC devices to the microelectronics industry, develop chip sets to be very flexible so as to fit a wide variety of applications and architectures. The chip suppliers do this by developing chip sets comprised of several single-function chips or sometimes a couple of functions per chip. For example, an existing commercially available V-Band (60 GHz) chip set consists of five or six single function devices. By using this approach, the subsystem architect can combine the “discrete” circuit functions appropriately to form a receiver or transmitter. Although this approach has flexibility, it also adds part count, manufacturing costs and can compromise performance, especially in the upper millimeter wave (mmw) bands.
A key to bringing E-Band based products to the market place is a low cost, repeatable, mass producible means of realizing the transceiver electronics. Currently, there are several packaging technologies which are currently being utilized to implement E-band applications, including: flip chip, MMIC, and coplanar technology.
Of the aforementioned technologies, MMIC technology is a leading choice because it greatly reduces component count, it lowers bill of materials cost, it lowers the cost of manufacturing/part placement, and it is easy to integrate into systems. Moreover, MMIC technology allows for repeatable testing processes, tight performance tolerances, it is physically smaller in size, and easy to implement advanced architectures.
It would be desirable to provide a highly integrated MMIC-based front-end transceiver integrated chip set for E-Band applications which is a high yield, repeatable MMIC chipset, compact in size and economical to manufacture. If such an E-Band chip set could be produced, the benefits of broadband technology would become more easily realized.